Swing mechanism for earth-moving apparatus

ABSTRACT

Switch mechanism for an earth-moving apparatus which comprises a main frame and a swing frame mounted for horizontal swinging movement about first substantially vertical pivot means on the main frame. It includes means for carrying a pair of elongate flexible means, such as chains or cables, which is pivotally mounted adjacent to one end of the main frame by second substantially vertical pivot means and has an arcuate peripheral portion at its other end. A single ram-type hydraulic motor means has one end mounted for pivotal movement on the main frame and its other end mounted for pivotal movement on the carrying means. One end of each of the elongate flexible means is attached to the swing frame and one end of each is attached to the arcuate peripheral portion of the carrying means whereby movement of the carrying means about the second vertical pivot means by the motor causes the swing frame to swing about the first substantially vertical pivot means.

[ July 15, 1975 1 1 SWING MECHANISM FOR EARTH-MOVING APPARATUS [75] Inventor: John S. Pilch, Ware. Mass.

[73] Assignee: Ware Machine Service, Inc.. Ware.

Mass.

[22] Filed: Apr. 11, 1974 [21] Appl. No.: 460,219

Primary Examiner-Robert R. Song [57} ABSTRACT Switch mechanism for an earth-moving apparatus which comprises a main frame and a swing frame mounted for horizontal swinging movement about first substantially vertical pivot means on the main frame. It includes means for carrying a pair of elongate flexible means, such as chains or cables, which is pivotally mounted adjacent to one end of the main frame by second substantially vertical pivot means and has an arcuate peripheral portion at its other end. A single ram type hydraulic motor means has one end mounted for pivotal movement on the main frame and its other end mounted for pivotal movement on the carrying means. One end of each of the elongate flexible means is attached to the swing frame and one end of each is attached to the arcuate peripheral portion of the carrying means whereby movement of the carrying means about the second vertical pivot means by the motor causes the swing frame to swing about the first sub stantially vertical pivot means.

15 Claims, 6 Drawing Figures PMEHTEDJUL z 5 ms SHEET ATE? WEQJUL i 5 1975 SHEET mmm SWING MECHANISM FOR EARTH-MOVING APPARATUS BACKGROUND OF THE INVENTION This invention relates to a swing mechanism for earth-moving apparatus such as backhoes, cranes, derricks or the like which include an earth-moving implement, such as a bucket or other tool, associated with the remote end of a boom.

Such an apparatus commonly includes a main frame adapted to be attached to a vehicle such as a tractor. a swing frame which carries the boom and substantially vertical pivot means connecting the main frame and the swing frame for swinging movement of the swing frame about said pivot means. This permits swinging the boom to either side through a total angle of approximately 180. The swing frame mechanism conventionally is powered by two ram-type hydraulic motor means. Such an apparatus also commonly includes two elongate flexible means, such as chains or cables, one having one end attached to one of the hydraulic motor means and the other end attached to the swing frame and the other having one end attached to the other hydraulic motor means and the other end attached to the swing frame. Thus, one of the motor means causes one of the elongate flexible means to rotate the swing frame means in one direction and the other motor means retains the tautness of the other elongate flexible means in the other direction and vice versa.

Such apparatus are disclosed in my U.S. Pat. No. 3,042,236 and in U.S. Pat. Nos. to McLaughlin 3,430,503 and Dorkins 3,250,410 (FIGS. 7 to 12). In the apparatus of each of these patents, the longitudinal axes of the hydraulic motor means extend substantially parallel to the plane of the longitudinal axis of the boom when the swing frame means is substantially at the center of its swinging movement and in the resultant apparatus the combined length of the swing frame and the main frame when viewed from the top is relatively long and results in a poorly balanced tractorbackhoe combination. In addition each of these patents utilizes two hydraulic motor means.

The apparatus disclosed in my U.S. Pat. No. 2,801,013 also embodies two hydraulic motor means the longitudinal axes of which extend substantially parallel to the plane of the longitudinal axis of the boom when the swing frame is substantially at the center of its swinging movement resulting in the same deficien cies stated for the above three prior patents. It also requires the use ofa long chain adding to the cost of manufacture.

The apparatus disclosed in Przyblyski U.S. Pat. No. 2,655,269 utilizes two hydraulic motor means and two long cables which cross each other and which pass over four sheaves so it is both expensive to manufacture and to maintain.

The apparatus of Billings U.S. Pat. No. 2,365,168 includes two hydraulic motor means and two long cables which pass over six sheaves so it is subject to the same deficiencies as the Przyblyski apparatus.

While Pitman U.S. Pat. No. 2,559,733 discloses a device which utilizes only one double-acting ram-type hydraulic motor means, its cables are long, they cross each other and pass over four sheaves so the apparatus is expensive to manufacture and to maintain.

SUMMARY OF THE INVENTION One object of this invention is to provide a new and improved swing mechanism for an earthmoving apparatus.

Another object is to provide such an apparatus which is economical to manufacture, to maintain and to service.

A further object is to provide such an apparatus which employs only one ram-type hydraulic motor means.

Another object is to provide such an apparatus which is free from sheaves associated with the elongate flexible means used to swing the swing frame means.

A still further object is to provide such a swing mechanism which is compact.

Yet a further object is to provide new and improved means for adjusting and retaining the tautness of the elongate flexible means.

Other objects and advantages ofthe invention will be apparent to persons skilled in the art from the following description taken in conjunction with the accompanying drawings.

In general the swing mechanism embodying this invention comprises a main frame adapted to be carried by a vehicle, a swing frame. and first substantially vertical pivot means connecting the main frame and the swing frame for substantially horizontal movement of the swing frame relative to the main frame about the first substantially vertical pivot means. The mechanism also comprises means for carrying a pair of elongate flexible means, such as chains, cables or the like.

A second substantially vertical pivot means connects one end of the carrying means with the main frame for substantially horizontal pivotal movement of the carrying means relative to the main frame. The carrying means has an arcuate peripheral portion at its end which is opposite to the end through which the second substantially vertical pivot means passes.

The mechanism also comprises a single ram-type hydraulic motor means having one end mounted for pivotal movement on the main frame and its other end mounted for pivotal movement on the carrying means at a locality thereof between the second substantially vertical pivot means and the swing frame, one end of each of the elongate flexible means is attached to the swing frame, the other end of the first of the elongate flexible means is attached to a locality of the arcuate peripheral portion of the carrying means and the other end of the second of the elongate flexible means is attached to a locality of the arcuate peripheral portion of the carrying means which is spaced from the locality where said one end of the first elongate flexible means is attached thereto.

The swing frame also comprises a boom having one end pivotally attached to the swing frame permitting swinging movement of the boom in a substantially vertical plane.

In a preferred embodiment, the swing frame comprises a generally cylindrical member which is substantially coaxial with the first substantially vertical pivot means, and when the swing frame is substantially at the center of its swing and the apparatus is viewed from the top, each of the elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom and the second substantially vertical pivot means, and thence about the arcuate peripheral portion of the carrying means to the locality of attach merit of its end thereto. In this embodiment the side of the elongate flexible means which is most remote from the arcuate peripheral portion of the carrying means contacts the arcuate peripheral face of the generally cylindrical member substantially from the locality where it crosses said plane and proceeds thence in a substantially horizontal direction in contact with the arcuate peripheral face of the generally cylindrical member.

Preferably the generally cylindrical member is mounted to provide a gap between the arcuate portion of the carrying means and the adjacent portion of the arcuate face of the generally cylindrical member the width of which is only slightly greater than the thickness of the elongate flexible means when viewed from the top and portions of the pair of elongate flexible means are located in this gap during all pivotal movements of the carrying means, whereby the distance between the axis of the first vertical pivot means and the face of the carrying means is reduced thereby to provide a compact apparatus when viewed from the top.

Preferably the ends of the elongate flexible means are attached to localities near opposite ends of the arcuate peripheral portion of the carrying means and their other ends are attached to localities of the swing frame means, whereby the lengths of the flexible means are reduced.

In a preferred embodiment means is provided on the swing frame associated with one end of at least one of the elongate flexible means for adjusting the tautness of that flexible means. A similar adjustment means may be associated with the end of the other elongate flexible means.

According to a preferred embodiment the longitudinal centerline of at least one of the elongate flexible means is in a different plane from the plane of the longitudinal centerline of the hydraulic motor means when viewed from the front. The longidunal centerlines of both elongate flexible means may be in different planes from the longitudinal centerline of the hydraulic motor means.

Preferably the pair of elongate flexible means are attached to the swing frame means so that they extend in spaced substantially parallel planes when viewed from the front.

In a preferred embodiment, the pair of elongate flexible means are attached to the arcuate peripheral portion of the carrying means so that their longitudinal centerlines extend in substantially parallel planes when viewed from the front and they remain in such spaced planes throughout all swinging movements of the swing frame means.

Preferably the distance between the longitudinal cen' terlines of the pair of elongate flexible means is greater than the height of one elongate flexible means when viewed from the front.

The apparatus is free from sheaves for coaction with the elongate flexible means.

In a preferred embodiment one end of the first elongate flexible means is attached adjacent to one end of the arcuate peripheral portion of the carrying means and the other end of said first elongate flexible means is attached to a side of the swing frame means which is remote from that end of the arcuate peripheral portion, one end of the second elongate flexible means is attached adjacent to the other end of the arcuate peripheral portion of the carrying means and the other end of the second elongate flexible means is attached to the opposite side of the swing frame means, whereby short elongate flexible means may be used.

A swing frame mechanism embodying this invention utilizes only one double-acting ram-type motor means, is free from sheaves associated with the elongate flexible means, is economical to manufacture, service and maintain, is compact, includes means for adjusting and retaining the tautness of the elongate flexible means and otherwise fulfills or satisfies the above stated objects and advantages.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view showing a swing mechanism for an earth-moving apparatus embodying this invention',

FIG. 2 is a front elevation of the apparatus shown in FIG. 1',

FIG. 3 is a top plan view of the apparatus of FIG. 1 but with the swing frame means swung from its position in FIGS. 1 and 2;

FIG. 4 is an end view taken on the line 4-4 of FIG.

FIG. 5 is a diagrammatic plan view showing the means for carrying a pair of elongate flexible means and the attachments of the ends of the upper elongate flexible means to that member and to the swing frame means respectively; and

FIG. 6 is a diagrammatic plan view similar to FIG. 5 but showing the attachments of the ends of the lower elongate flexible means to the means for carrying a pair of elongate flexible means and to the swing frame means respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings, wherein similar reference characters designate corresponding parts throughout, the invention relates to a swing mechanism for earthmoving apparatus such as backhoes, cranes, derricks, or the like which include an earth-moving implement such as a bucket or other tool associated with the remote end of a boom.

The swing mechanism of the present invention is shown applied to a backhoe having a main frame 10 which may be permanently built onto the rear of an industrial type tractor or may be a separate unit adapted to be attached thereto. In the embodiment shown in the drawings, the main frame 10 is a separate unit the ends 13 of which are provided with a pair of orifices 11 and a pair of semicircular grooves 12 (FIG. 4) adapted to receive bolts for securing the main frame to the rear of a tractor.

The main frame is provided with conventional stabilizer legs 15 projecting laterally from each side thereof which are forced by double-acting ram-type hydraulic motor means 16 into contact with the ground when the backhoe is being used. Only the rods of these hydraulic motor means and segments of the stabilizer legs are shown in the drawings since such hydraulic motor means and stabilizers are well known in the art.

A swing frame I8 is pivotally mounted on the main frame by a pair of vertically extending pivots 20-20 which pass through the elements 21 of the swing frame and the outwardly extending projections 22 which are secured to upper and lower members 23. 24 of the main frame (FIGS. 1 and 2).

The horizontal pivot pin 26 which passes through the sides 18A of the swing frame and the lower ends of the backhoe boom supports the boom for vertical swinging movement. A double-acting ram-type hydraulic motor means 27 is pivotally connected between the sides 18A of the swing frame by the horizontal pivot pin 28. Only the rod portion of the ram of this hydraulic motor means is shown in the drawings because such motor means are well known in the art for use in swinging a boom about a horizontal pivot such as 26. A bucket or other earth-moving implement (not shown) is attached to a dipperstick (not shown) which in turn is attached to the upper end of the boom by conventional means (not shown).

The boom and swing frame can be swung about the vertical pivot means 20 through an arc of substantially I80 to positions where the boom is substantially parallel to the face of the main frame, one such position being shown in FIG. I. At the center of such swinging movement the boom is in the position shown in FIG. 3.

The means 30 for carrying a pair of elongate flexible means 50 and 51 has one end pivotally connected between a pair of extensions 3] (FIG. 4) of the main frame by a pin 32 which constitutes a second substantially vertical pivot means. Thus the carrying means 30 is supported for substantially horizontal pivotal movement relative to the main frame. The carrying means 30 has an arcuate peripheral portion 30A at its end which is opposite to its end which is connected to the extensions 31 (FIGS. 1 and 4).

A single ram-type hydraulic motor means has its cylinder 34A mounted for pivotal movement with respect to the main frame by the pin 35 and lugs 36 which are secured to one end of the main frame. Its rod 343 has one end mounted for pivotal movement with respect to the carrying means 30 by the pin 37 which extends through a pair of lugs 37A which are attached to the carrying means (FIGS. 1 and 2). As appears from FIG. 3 the pin 37 is located between the second vertical pivot means 32 and the swing frame.l8 when the swing frame is at the center of its swinging movement.

The piston 34C (FIG. 4) of the hydraulic motor means is secured to the rod 34B. Oil or other fluid under pressure is supplied periodically through hoses (not shown) from a source of'fluid under pressure (not shown) through the connections 34D (FIGS. 1 to 3) to the interior of the cylinder 34A. This oil acting against the piston 34C causes the rod to move and this causes the carrying means 30 to be pivoted about the second vertical pivot means 32, for example from the position shown in FIG. I to the position shown in FIG. 3, and then back to the position shown in FIG. I.

The swinging movement of the swing frame about the first vertical pivot means 20 is caused by a pair of elongate flexible means such as the pair of chains 50 and 51. While chains are shown in the drawings, cables or other elongate flexible means may be used.

A generally cylindrical member 55 is secured to the swing frame with its axis substantially coaxial with the first vertical pivot means 20. It is mounted so that the gap between the face of the arcuate peripheral portion 30A of the carrying means and the adjacent arcuate face of the generally cylindrical member 55 is only slightly greater than the thickness of each chain when viewed from the top as in FIGS. 1 and 3 thereby to provide a compact device.

One end of the upper chain 50 is attached to the generally cylindrical member 55 by a bolt 55A which passes through a boss 55A secured between one of the side members 18A of the swing frame and the generally cylindrical member and has its end secured to the end of the chain (FIGS. 1, 3 and 5). The other end of this chain is attached to the arcuate peripheral portion 30A of the carrying means by the lug 50B and a pin 50C (FIGS. 3. 4 and 5). Thus the tautness of the chain may be adjusted by adjusting the bolt 50A.

The lower chain SI has one end attached to the swing frame by a bolt 51A which passes through a boss 558 secured between one of the side members ISA of the swing frame and the generally cylindrical member 55 and has its end secured to the end of the chain 51 (FIGS 1, 3 and 6). The other end of the lower chain SI is attached to the lug 518 provided on the other end of the arcuate peripheral portion 30A of the carrying means by a pin 51C (FIGS. 1, 3 and 6). The tautness of the lower chain may be adjusted by adjustment of the bolt 51A.

Thus it will be observed that one end of each chain is attached to the swing frame means and the other end is attached to the means 30 for carrying a pair of elongate flexible means and consequently when the carrying member is rotated in one direction about the second vertical pivot means 32 by admission of oil under pressure into one end of the cylinder 34A. the swing frame 18 is swung in one direction about the first vertical pivot means 20 and when the oil is admitted to the opposite end of the cylinder. the carrying member is moved in the opposite direction about the second vertical pivot means causing the swing frame to be swung in the opposite direction. The amount of swing in either direction may be controlled by the operator who is provided with a control valve (not shown) for directing the hydraulic fluid through hoses into one or the other of the inlets 34D.

When the swing frame 18 is substantially at the center ofits swing and the apparatus is viewed from the top as in FIG. 3 each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom and the second substantially vertical pivot means 32, and thence about the arcuate peripheral portion 30A of the carrying means 30 to the locality of attachment of its end thereto (50C or SIC) so that during each unit of pivotal movement of the carrying means in one direction a substantially equal unit of one of the elongate flexible means is unwound from the generally cylindrical member and a substantially equal unit of the other of said elongate flexible means is wound upon the generally cylindrical member. The equivalent result occurs upon movement of the carrying means in the opposite direction.

The side of each elongate flexible means which is most remote from the arcuate peripheral portion 30A of the carrying means contacts the arcuate peripheral face of the generally cylindrical member 55 substantially from the locality where it crosses the plane through the longitudinal centerline of the boom and the vertical pivot means 32 when the swing frame is substantially at the center of its swing as shown in FIG. 3 and the flexible means proceeds thence in a substantially horizontal direction in contact with the arcuate peripheral face.

As shown in FIGS. 1, 3 and 4 the generally cylindrical member 55 of the swing frame is mounted to provide a gap between the face of the carrying means and the adjacent portion of the arcuate face of the generally cylindrical member the width of which is only slightly greater than the thickness of each chain when viewed from the top and portions of the pair of chains are located in that gap during all pivotal movements of said carrying means, so that the distance between the axis of the first vertical pivot means and the face of the carrying means is reduced thereby to provide a compact apparatus.

It will be observed from FIGS. 2 and 4 that the distance between the longitudinal centerlines of the chains 50 and 51 when viewed from the front is greater than the height of one of the chains.

It will be observed that because the ends of the chains are attached to localities 50C and 51C near opposite ends of said arcuate peripheral portion A of the carrying means and their other ends are attached to the localities 55A and 55B of the swing frame the lengths of the chains are reduced.

The tautness of the chains may be adjusted by the bolts 50A and 51 respectively As shown in FIGS. 2 and 4 the longitudinal center lines of at least one of the chains is in a different plane from the plane of the longitudinal centerline of the hydraulic motor means 34A, 34B and that the chains extend in spaced substantially parallel planes when the apparatus is viewed from the front.

The chains are also attached to the arcuate peripheral portion 30A of the carrying means so that their longitudinal centerlines extend in substantially parallel planes when viewed from the front.

The longitudinal centerlines of the chains are in spaced planes when viewed from the front and they remain in spaced planes throughout all swinging movements of the swing frame.

The apparatus is free from sheaves for coaction with the elongate flexible means.

Referring to FIGS. 3, 5 and 6, one end of the first elongate flexible means 50 is attached adjacent to one end of the arcuate peripheral portion 30A of the carrying means at 50C and the other end thereof is attached at 50A to a side of the swing frame means which is remote from that end of the arcuate peripheral portion, one end of the second elongate flexible means 51 is attached at 51C adjacent to the other end of the arcuate peripheral portion of the carrying means and the other end thereof is attached to the opposite side of the swing frame means. whereby short elongate flexible means may be used.

A swing frame mechanism embodying this invention utilizes only one double-acting ram-type motor means, is free from sheaves associated with the elongate flexible means, is economical to manufacture, service and maintain, is compact. includes means for adjusting and retaining the tautness of the elongate flexible means and otherwise fulfills all of the above stated objects and advantages.

While one desirable embodiment of the invention has been shown and described, it is to be understood that this disclosure is for the purpose ofillustration only and that various changes in shape, proportion and arrangement of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. In swing mechanism for an earth-moving apparatus comprising,

a main frame adapted to be carried by a vehicle,

swing frame means, and

first substantially vertical pivot means connecting said main frame and said swing frame means for substantially horizontal movement of said swing frame means relative to said main frame about said substantially vertical pivot means,

the improvement comprising,

a pair of elongate flexible means,

means for carrying said pair of elongate flexible means,

second substantially vertical pivot means connecting one point of said carrying means with said main frame for substantially horizontal pivotal movement of the carrying means relative to said main frame, said carrying means having an arcuate peripheral portion on one end,

a single ram-type hydraulic motor means having one end mounted for pivotal movement on the main frame and its other end mounted for pivotal movement on said carrying means at a locality spaced from said second substantially vertical pivot means and said swing frame means,

one end of each of said pair of flexible means being attached to said swing frame means, the other end of the first of said elongate flexible means being attached to a locality of said arcuate peripheral portion of said carrying means and the other end of the second of said elongate flexible means being attached to a locality of said arcuate peripheral portion of said carrying means which is spaced from the locality where said one end of said first elongate flexible means is attached.

boom means having one end pivotally attached to said swing frame means permitting movement of said boom in a substantially vertical plane,

said first substantially vertical pivot means being located at a forward portion of said main frame and said second substantially vertical pivot means being located at a rearward portion of said main frame, and

said pair of elongate flexible means crossing each other when the mechanism is viewed from the top,

whereby pivotal movement of said means for carrying about said second substantially vertical pivot means by said hydraulic motor means causes said swing frame means to swing about said first substantially vertical pivot means.

2. Apparatus according to claim I wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said first substantially vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom and said second substantially vertical pivot means, and thence about the arcuate peripheral portion of said carrying means to the locality of attachment of its end thereto. whereby during each unit of pivotal movement of the carrying means a substantially equal unit of one of said elongate flexible means is unwound from the generally cylindrical member and a substantially equal unit of the other of said elongate flexible means is wound upon the generally cylindrical member.

3. Apparatus according to claim 1 wherein the side of the elongate flexible means which is most remote from the arcuate peripheral portion of the carrying means contacts the arcuate peripheral face of the generally cylindrical member substantially from the locality where it crosses said plane and proceeds thence in a substantially horizontal direction in contact with said arcuate peripheral face.

4. Apparatus according to claim 1 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said first vertical pivot means and is mounted to provide a gap between the face of said carrying means and the adjacent por' tion of the arcuate face of said generally cylindrical member the width of which is only slightly greater than the thickness of said flexible means when viewed from the top and wherein portions of said pair of flexible means are located in said gap during all pivotal movements of said carrying means, whereby the distance between the axis of said first vertical pivot means and the face of said carrying means is reduced thereby to provide a compact apparatus when viewed from the top.

5. Apparatus according to claim 4 wherein ends of said flexible means are attached to localities near opposite ends of said arcuate peripheral portion of said carrying means and their other ends are attached to localities of said swing frame means, whereby the lengths of said flexible means are reduced.

6. Apparatus according to claim 1 which also comprises means on the swing frame means associated with one end of at least one of said flexible means for adjusting the tautness of said one flexible means.

7. Apparatus according to claim 1 wherein the longi tudinal centerline of at least one of said elongate flexible means is in a different plane from the plane of the longitudinal centerline of the hydraulic motor means when viewed from the front.

8. Apparatus according to claim 1 wherein said pair of elongate flexible means are attached to said swing frame means so they extend in spaced substantially parallel planes when viewed from the front.

9. Apparatus according to claim 1 wherein the longitudinal centerlines of said elongate flexible means are in spaced planes when viewed from the front and they remain in spaced planes throughout all swinging movements of said swing frame means.

10. Apparatus according to claim I wherein the distance between the longitudinal centerlines of the pair of elongate flexible means when viewed from the front is greater than the height of one elongate flexible means.

11. Apparatus according to claim 1 which is free from sheaves for coaction with the elongate flexible means.

12. Apparatus according to claim I wherein one end of the first elongate flexible means is attached adjacent to one end of the arcuate peripheral portion of said carrying means and the other end of said first elongate flexible means is attached to a side of the swing frame means which is remote from said one end of said arcuate peripheral portion, one end of the second elongate flexible means is attached adjacent to the other end of said arcuate peripheral portion and the other end of said second elongate flexible means is attached to the opposite side of said swing frame means.

13. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached to a first locality of said arcuate peripheral portion of said carrying means and one end of the second elongate flexible means is attached to a second locality of said arcuate peripheral portion which is spaced from said first locality, the other end of said first elongate flexible means being attached to a first locality of said swing frame means and the other end of said second elongate flexi ble means being attached to a second locality of said swing frame means which is spaced from the locality of attachment of said other end of said first elongate flexi ble means to said swing frame means whereby pivotal movement of said carrying means in one direction about said second substantially vertical pivot means causes one of said elongate flexible means to rotate said swing frame means in one direction about said first sub stantially vertical pivot means and retains the tautness of the other elongate flexible means in the other direc tion and the tautness of both of said flexible means is thereby maintained at all times.

14. Apparatus according to claim I wherein one end of the first elongate flexible means is attached at a first point adjacent to one end of said arcuate peripheral portion of said carrying means and one end of the second elongate flexible means is attached to a second point adjacent to the other end of said arcuate peripheral portion and the distance between said first point and the axis of said first vertical pivot means is greater than the distance between said second point and the axis of sais first vertical pivot means when the swing frame means and the boom have been swung to the full extent of their swing in one direction.

15. Apparatus according to claim 1 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said vertical pivot means, and when said swing frame means is sub stantially at the center of its swing and the apparatus is viewed from the top each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through said first and second substantially vertical pivot means, whereby when the swing frame and boom have been swung to the full extent of their swing in one direction the portion of one elongate flexible means which engages said arcuate peripheral face is greater than the length of the remainder of that elongate flexible means.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3, 894,641

DATED July 15, 1975 INVENTOR( 1 John S. Pilch It is certified that error appears in the aboveqdentifred patent and that said Letters Patent are hereby corrected as shown below.

[57] Abstract, line 1, "Switch" should read "Swing"; line 17 after "motor" insert .means.

Signed and Scaled this sixteenth D3) Of September 1975 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN AIM-sting Officer (mnnu'sslmu-r njPatenrs and Trademarks 

1. In swing mechanism for an earth-moving apparatus comprising, a main frame adapted to be carried by a vehicle, swing frame means, and first substantially vertical pivot means connecting said main frame and said swing frame means for substantially horizontal movement of said swing frame means relative to said main frame about said substantially vertical pivot means, the improvement comprising, a pair of elongate flexible means, means for carrying said pair of elongate flexible means, second substantially vertical pivot means connecting one point of said carrying means with said main frame for substantially horizontal pivotal movement of the carrying means relative to said main frame, said carrying means having an arcuate peripheral portion on one end, a single ram-type hydraulic motor means having one end mounted for pivotal movement on the main frame and its other end mounted for pivotal movement on said carrying means at a locality spaced from said second substantially vertical pivot means and said swing frame means, one end of each of said pair of flexible means being attached to said swing frame means, the other end of the first of said elongate flexible means being attached to a locality of said arcuate peripheral portion of said carrying means and the other end of the second of said elongate flexible means being attached to a locality of said arcuate peripheral portion of said carrying means which is spaced from the locality where said one end of said first elongate flexible means is attached, boom means having one end pivotally attached to said swing frame means permitting movement of said boom in a substantially vertical plane, said first substantially vertical pivot means being located at a forward portion of said main frame and said second substantially vertical pivot means being located at a rearward portion of said main frame, and said pair of elongate flexible means crossing each other when the mechanism is viewed from the top, whereby pivotal movement of said means for carrying about said second substantially vertical pivot means by said hydraulic motor means causes said swing frame means to swing about said first substantially vertical pivot means.
 2. Apparatus according to claim 1 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said first substantially vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom and said second substantially vertical pivot means, and thence about the arcuate peripheral portion of said carrying means to the locality of attachment of its end thereto, whereby during each unit of pivotal movement of the carrying means a substantially equal unit of one of said elongate flexible means is unwound from the generally cylindrical member and a substantially equal unit of the other of said elongate flexible means is wound upon the generally cylindrical member.
 3. Apparatus according to claim 1 wherein the side of the elongate flexible means which is most remote from the arcuate peripheral portion of the carrying means contacts the arcuate peripheral face of the generally cylindrical member substantially from the locality where it crosses said plane and proceeds thence in a substantially horizontal direction in contact with said arcuate peripheral face.
 4. Apparatus according to claim 1 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said first vertical pivot means and is mounted to provide a gap between the face of said carrying means and the adjacent portion of the arcuate face of said generally cylindrical member the width of which is only slightly greater than the thickness of said flexible means when viewed from the top and wherein portions of said pair of flexible means are located in said gap during all pivotal movements of said carrying means, whereby the distance between the axis of said first vertical pivot means and the face of said carrying means is reduced thereby to provide a compact apparatus when viewed from the top.
 5. Apparatus according to claim 4 wherein ends of said flexible means are attached to localities near opposite ends of said arcuate peripheral portion of said carrying means and their other ends are attached to localities of said swing frame means, whereby the lengths of said flexible means are reduced.
 6. Apparatus according to claim 1 which also comprises means on the swing frame means associated with one end of at least one of said flexible means for adjusting the tautness of said one flexible means.
 7. Apparatus according to claim 1 wherein the longitudinal centerline of at least one of said elongate flexible means is in a different plane from the plane of the longitudinal centerline of the hydraulic motor means when viewed from the front.
 8. Apparatus according to claim 1 wherein said pair of elongate flexible means are attached to said swing frame means so they extend in spaced substantially parallel planes when viewed from the front.
 9. Apparatus according to claim 1 wherein the longitudinal centerlines of said elongate flexible means are in spaced planes when viewed from the front and they remain in spaced planes throughout all swinging movements of said swing frame means.
 10. Apparatus according to claim 1 wherein the distance between the longitudinal centerlines of the pair of elongate flexible means when viewed from the front is greater than the height of one elongate flexible means.
 11. Apparatus according to claim 1 which is free from sheaves for coaction with the elongate flexible means.
 12. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached adjacent to one end of the arcuate peripheral portion of said carrying means and the other end of said first elongate flexible means is attached to a side of the swing frame means which is remote from said one end of said arcuate peripheral portion, one end of the second elongate flexible means is attached adjacent to the other end of said arcuate peripheral portion and the other end of said second elongate flexible means is attached to the opposite side of said swing frame means.
 13. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached to a first locality of said arcuate peripheral portion of said carrying means and one end of the second elongate flexible means is attached to a second locality of said arcuate peripheral portion which is spaced from said first locality, the other end of said first elongate flexible means being attached to a first locality of said swing frame means and the other end of said second elongate flexible means being attached to a second locality of said swing frame means which is spaced from the locality of attachment of said other end of said first elongate flexible means to said swing frame means, whereby pivotal movement of said carrying means in one direction about said second sUbstantially vertical pivot means causes one of said elongate flexible means to rotate said swing frame means in one direction about said first substantially vertical pivot means and retains the tautness of the other elongate flexible means in the other direction and the tautness of both of said flexible means is thereby maintained at all times.
 14. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached at a first point adjacent to one end of said arcuate peripheral portion of said carrying means and one end of the second elongate flexible means is attached to a second point adjacent to the other end of said arcuate peripheral portion and the distance between said first point and the axis of said first vertical pivot means is greater than the distance between said second point and the axis of sais first vertical pivot means when the swing frame means and the boom have been swung to the full extent of their swing in one direction.
 15. Apparatus according to claim 1 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through said first and second substantially vertical pivot means, whereby when the swing frame and boom have been swung to the full extent of their swing in one direction the portion of one elongate flexible means which engages said arcuate peripheral face is greater than the length of the remainder of that elongate flexible means. 